With the decreasing size of electronic devices in general, the increasing density of component packing has required an increasing density of interconnections, especially to flat substrates such as printed circuit devices, etc. Since such interconnections are typically made by soldering, a reliable soldering technique for terminating conductors, especially multiaxial cables or twisted pairs, etc. to such substrates is desirable. It is especially desirable that any such terminations be strain-relieved and/or insulated.
In the past, various systems have been developed for simultaneously applying a plurality of bodies of solder. One such system is that disclosed in U.S. Pat. No. 3,396,894, which discloses the prepackaging of metered amounts of flux and solder in a heat-recoverable preformed polymer sheet which forces the solder into place. The patent teaches the use of discrete pieces of solder which must be precisely positioned above regions to be soldered. As heat is applied, the polymer sheet returns to its original flat configuration prior to solder melting.
U.S. Pat. No. 3,719,981 discloses an alternative method of applying solder balls, which are appropriately spaced on the tacky surface of a pressure-sensitive tape, to solder bumps used for connections.
Both of the above methods rely on the positioning of the small pieces of solder immediately adjacent to the terminals which are to be soldered, and, because small pieces of solder are used, each of the solder systems disclosed is difficult to manufacture.
U.S. Pat. No. 3,750,252 discloses the use of a single continuous piece of solder to simultaneously solder a large number of terminals. The solder wire extends along a terminal strip and, on heating, the solder melts and coalesces on the individual contacts to form independent connections.
U.S. application Ser. No. 158,034, filed Jun. 9, 1980, now U.S. Pat. No. 4,354,629 assigned to the assignee of the present invention, describes the use of a device having a continuous solder strip in contact with a polymeric layer having window means therein. In this application, the disclosure of which is incorporated herein by reference, the device is used to terminate multiconductor cables, and the window means control and direct the flow of solder.
U.S. patent application Ser. No. 172,897, filed July 28, 1980, now abandoned also assigned to the assignee of the present invention, describes a mass connector device comprising two layers of polymeric material, at least one of which is heat recoverable. In this application, the disclosure of which is incorporated herein by reference, the layers are bonded to form pockets, into which may be inserted substrates to be connected.